Zone-SDID Mapping for TLB Purge Efficiency
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Solution Overview
Problem
Conventional methods for TLB purges require storing zone information with each entry, leading to increased processing time and overhead due to the need to search and match zone information across multiple TLB entries, which is inefficient and power-consuming.
Innovation Solution
Implementing a zone-SDID mapping scheme that uses the existing zone register to compute an SDID vector from zone attribute information, allowing for the comparison and purge of TLB entries without the need to store zone information with each entry, thereby reducing the number of read operations and improving processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zone information is stored with each TLB entry, then TLB purges can be performed by comparing zone information, but processing time and overhead increase due to the need to search and match zone information across multiple TLB entries
Solution Approach 1:
The patent extracts the zone information storage function from individual TLB entries and relocates it to a separate zone register. The zone register stores zone information indexed by SDID (Segment Descriptor Identifier), allowing the TLB to perform purges by comparing SDIDs rather than storing and searching full zone information in each entry. This extraction reduces the data storage burden on each TLB entry while maintaining purge accuracy.
Solution Approach 2:
The zone register is pre-populated with zone information organized by SDID before TLB purge operations occur. This preliminary organization allows the purge mechanism to quickly retrieve and compare zone information without performing time-consuming searches during the actual purge operation. The zone register acts as a pre-computed lookup table that speeds up the purge process.
2Reliability
If zone information is stored with each TLB entry, then TLB purges can be performed, but the number of read operations increases leading to higher power consumption
Solution Approach 1:
The patent removes the requirement to read and compare zone information from each TLB entry during purge operations. Instead, zone information is extracted and stored in the zone register, which can be accessed efficiently by SDID. This reduces the number of read operations needed during TLB purges, thereby lowering power consumption while maintaining purge functionality.
Solution Approach 2:
The zone register creates a copy of the necessary zone information organized by SDID, separate from the TLB entries. This copy allows the purge mechanism to access zone information without reading it from each TLB entry, reducing the total number of read operations and associated power consumption while preserving the ability to perform accurate purges.
3Reliability
If zone information is stored with each TLB entry, then TLB purges can be performed by matching zone information, but the complexity of the purge mechanism increases
Solution Approach 1:
The patent extracts the zone information management function from the complex TLB entry structure and places it in a dedicated zone register. This separation simplifies the TLB entry format and the purge mechanism, as the purge operation now only needs to compare SDIDs and retrieve corresponding zone information from the zone register, rather than managing and searching zone information embedded in each TLB entry.
Solution Approach 2:
The zone register acts as an intermediary structure between the TLB and the purge mechanism. It mediates the purge operation by providing efficient SDID-based access to zone information, eliminating the need for complex searches through TLB entries. This intermediary simplifies the overall purge mechanism while maintaining accurate zone-based purge capability.
Data Source
AI summary
Embodiments include techniques for using a zone-SDID mapping for translation lookaside buffer (TLB) purges, the techniques include receiving a zone purge request, including zone attribute information, and searching for matching zone attribute information in a zone register using the zone purge request. The techniques also include computing, based at least in part on the search, a state descriptor identifier (SDID) vector for each matching zone of the zone register, and reading TLB entries referenced in the zone purge request. The techniques include comparing an SDID of the TLB entry against an SDID specified in the SDID vector, and purging the TLB entries based on the comparison.